A number of electronic devices have graphical user interfaces (GUIs). Such devices include, for example, personal computers (PC), televisions and mobile telephones. The user may interact with the device via the GUI using a user interface, for instance a touch sensitive pad, a keyboard, a mouse or a joystick. Many factors determine the most appropriate choice of user interface for a device, such as ease of use and speed of operation and the environment in which the device is used. The use of a mouse is suited to the selection of icons when using a desk-top personal computer. However, it is not so useful for a digital television set. For this, a remote control unit having several keys is more convenient.
However, there are problems with using key- or button-based control units, as will now be explained with reference to digital television.
Digital television systems provide a variety of new services as compared with analogue television. They allow the user to transmit and receive signals via a set-top box and to interact with service providers. The user may now access the Internet in a similar way that is already available on a PC. For example, a user may navigate web pages by selecting hypertext links. The process of selecting a particular link involves moving a focus between links and activating selection. In a PC-based system, this process is realised by positioning a mouse pointer over the link and pressing the mouse button. To indicate that the focus has moved to the link, the shape of the mouse pointer changes or the link is highlighted, for instance, by changing colour.
The set-top box/television system is controlled using a remote control unit, which is similar to that used in analogue television systems. The remote control is usually provided with a set of arrow keys—up, down, right, left—allowing orthogonal movement about a menu.
Such a remote control unit provides a satisfactory means for selecting elements of the menu if the menu is arranged as a rectangular array along co-ordinates defined by the keys on the remote control. Elements in a column are selected by the use of up and down arrow keys, while elements along a row may be selected by use of right and left arrow keys. Thus, movement from one element to another is straightforward and intuitive.
However, the remote control unit is not suited to the selection of irregularly positioned elements, such as hypertext links in a web page.
To select a link, the user moves the focus to the link. If the focus is in the form of a pointer, such as an arrow or a cursor, the user positions the focus over the link using the arrow keys. However, this method of navigation is difficult since movement of the pointer is limited to the directions defined by the arrow keys. Furthermore, positioning of the pointer over the link becomes more difficult as the size of the link decreases. This problem may be avoided if the arrow keys are used to “step” the focus from one link to another in which case the link in focus is indicated by highlighting it in a different colour. However, this method of navigation has its own problems. Not only is this method slow, but it is also unpredictable.
Both these methods of navigation share another problem. While the user is navigating a web page, they usually concentrate on the focus. As the focus moves, the user's eye follows it. However, the user has to find the focus before they can navigate. This can happen for example when a web page is first downloaded, if the user restarts navigating a web page or if the focus unexpectedly jumps. Under these circumstances it can be difficult to locate the focus, whether it be a pointer or a highlighted link.
The present invention seeks to help overcome these problems.